Blender 2.78 video editor crash
A few things to consider are:
 Are you using an official release?
 Are you in the latest version or in an old verion? There is both Blender 2.78a and 2.78b now. I have been working in the video editor with 2.78b and have had no trouble. Try download and re-installing the latest verion. If it continues, try with a different video file. If the problem is fixed, then it means that your video file was damaged. It could also be your audio file... Hope this helps! :)

-Tovin